pion

noun
  1. A pion is a type of meson, which is a subatomic particle made up of a quark and an antiquark. Pions are responsible for mediating the strong nuclear force that holds atomic nuclei together. noun
    The pion plays a crucial role in the interactions between protons and neutrons within the nucleus.
    Pions are produced in high-energy collisions, such as those in particle accelerators.
  2. In a more general or informal context, 'pion' can also refer to a foot soldier or infantryman, derived from the French word 'pion', meaning pawn or foot soldier. noun
    In the medieval army, the pion was often tasked with carrying out the orders of higher-ranking officers.
    The term 'pion' was used historically to describe soldiers who were considered expendable in battle.